nzbget: add devel and test, make conf persistent

Add development release, add test, install configuration file in ```#{HOMEBREW_PREFIX}/etc``` so that it persists after upgrades and removals (was previously installed to the Cellar), use Homebrew's OpenSSL by default, change format of ```make``` commands.
I did this in a separate commit in case the maintainers want to exclude it. I'd personally prefer to have the extra ciphers and improved performance of the newer OpenSSL, but it can be left out or I can change it to ```:optional``` if that's preferred.